Black cohosh (Cimicifuga racemosa)

What it is Black cohosh, a member of the buttercup family, grows wild in the Eastern forests of the United States. With its 6-foot spikes of delicate white flowers, the plant is a striking sight when it blooms in late summer. The knobby black root of black cohosh has been used for centuries to treat women’s health conditions; now research is proving it to be one of the best natural alternatives to conventional hormone replacement therapy (HRT).

History and folk remedies Native Americans used black cohosh to treat a wide variety of health problems, including arthritis, backache, sore throat, fever, and even snakebite. Native American women relied on the herb to ease premenstrual symptoms and cramps and to stimulate contractions and alleviate pain following childbirth.

European colonists began using black cohosh in similar ways. The herb’s popularity skyrocketed in 1876 when a Massachusetts folk herbalist concocted a patent medicine for women using black cohosh as the primary ingredient. The medicine, Lydia E. Pinkham’s Vegetable Compound, became one of the best-selling patent medicines ever made.

Why it’s used Today, black cohosh is primarily used to treat the transition through menopause, reducing symptoms such as hot flashes and vaginal dryness. Many women are turning to black cohosh as an alternative to synthetic hormones, which received a wave of bad press two years ago following the federal government’s decision to shut down a large, long-term study of women taking HRT. The National Institutes of Health found that conventional HRT increases the risks of breast cancer, heart attacks, strokes, and blood clots in the lungs and legs.

How it works Researchers have long believed that black cohosh contains phytoestrogens, plant compounds that behave similarly to estrogen in the body. Because estrogen production sharply declines during menopause, phytoestrogens can help ease menopausal symptoms. But studies have produced contradictory results, and scientists haven’t definitively concluded whether the herb has estrogenic properties.

Other studies have shown that black cohosh appears to lower levels of luteinizing hormone (LH), a hormone produced by the pituitary gland that increases during menopause and contributes to menopausal symptoms.

Scientific support More than 20 clinical studies involving upward of 3,000 women have evaluated the effects of black cohosh on menopausal symptoms. Most of the studies used the Kupperman Menopausal Index, a self-assessment tool that charts hot flashes, sweating, insomnia, nervousness, irritability, depression, vertigo, poor concentration, arthritic pain, headaches, and heart palpitations—all common complaints during menopause. Although the results showed that black cohosh extract is significantly more effective than a placebo and on par with HRT in providing symptom relief, some researchers have criticized the studies for being poorly designed.

However, the evidence in favor of black cohosh is compelling enough that the National Center for Complementary and Alternative Medicine at the National Institutes of Health is funding a rigorous 12-month study to determine the effects of the herb on hot flashes and other menopausal symptoms. (Women interested in participating in the study can find out more at www.clinicaltrials.gov.) In 2001, the American College of Obstetricians and Gynecologists approved the use of black cohosh for up to six months as a treatment for menopausal hot flashes. According to the Herb Research Foundation, black cohosh traditionally has been used for longer periods of time without toxicity or harmful side effects.

How to take it Black cohosh is most effective when taken in liquid extract, tablet, or capsule form, rather than as a tea. Most studies have used a standardized extract; because preparations vary in potency and formulation, it’s best to follow the manufacturer’s recommended dosages.

Side effects Occasionally, black cohosh can cause mild stomach upset. In amounts greater than the recommended dosages, the herb may cause headache, nausea, dizziness, and impaired circulation. Black cohosh should not be used during pregnancy.